The present principles generally relate to optical systems, and more particularly, to a system and method for alignment of optical elements in relation to each other in an optical device using references on the optical elements.
Within the art of optical device design, multiple optical lenses are commonly used together in a variety of optical devices. Multiple lenses (often referred to as a “lens train”) are commonly used in optical devices such as cameras, telephoto lenses, binoculars, telescopes, microscopes, night vision scopes, vehicular and marine periscopes, and the like.
When fabricating optical devices with multiple lenses, the alignment of each individual lens relative to the other lenses in the lens train is critical to achieving the desired optical performance. FIG. 1a illustrates a pair of lenses 108, 110 in a lens train 100, in which the lenses 108, 110 are properly aligned with each other. A viewed object 102 falls within the confines of a field of view 104. Light reflecting off of the viewed object 102 passed through the first lens 108 and is magnified to create an intermediate image (not shown). The intermediate image is then focused onto a second lens 110 which performs additional magnification or other optical modification of the intermediate image, resulting in a final displayed image 112. When properly aligned, the first lens 108 focuses an image of the object 102 onto the second lens 110 in a predictable and acceptable manner. Centerline 106 illustrates a path that may be ideal for referencing alignment of the first lens 108 and the second lens 110. In contrast, FIG. 1b illustrates the lens train 100 with the first lens 114 misaligned with respect to the second lens 110. Accordingly, misaligned first lens 114 does not properly focus an intermediate image onto the second lens 110, resulting in an off-center and/or distorted displayed image 116.
The current state of the art teaches methods for aligning lenses with respect to other elements of an optical device using precision housings and the like. In particular, with the rise of inexpensive digital cameras, many manufacturers have attempted to align camera lenses with optical sensors by providing a precision alignment surface within the housing of the camera. Precision alignment of lenses in the current state of the art requires the lens housing to be manufactured to high tolerances in order to provide a high tolerance fit between the housing and the lenses. The necessity of providing precision lens housings results in an increased manufacturing cost.